ADjusting the sampling rate on a FIR filter?

[senior lab project]

How do I adjust the sampling rate on a digital FIR filter? Thanks in advance.

-David

[Zvezdana S.]

David,
The digital FIR filter doesn't allow you to specify the sampling rate. It determines the signal sampling rate based on the Signal In input.
dt will determine the maximum frequency you can handle in your filter, Fmax = (1/2)*dt
This frequency is fed into the ma_design FIR Coeff.vi inside Design FIR Filter.vi.

Zvezdana S.

[suni]

Hi

In my application i am filtering a signal which is sampled at 100s/s. For the filter i am using DFD build a filter form transfer function.vi. Does that mean my filter is sampling at 100s/s also? If i change my signal sampling rate does filter change its sampling rate automatically?

[Dennis_Knutson]

You should really start a new thread instead of posting to one that is 5 years old.

To answer your question, it depends on your data. I don't use the DFD but with the filter functions in LabVIEW, if you pass a waveform data type to the function, then the waveform data type contains a dt value. So, set the DAQmx Read to return waveform data. If you are using low level filter functions where the input is a 1D DBL array, then the filter has to be configured. With the low level functions in LabVIEW, you use the various coefficients functions that have a sampling frequency input.